1/*
2 *
3 * Copyright 2024 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19package internal
20
21import (
22 "encoding/json"
23 "fmt"
24 "io"
25 "log"
26 "os"
27)
28
29// LoggerV2 does underlying logging work for grpclog.
30type LoggerV2 interface {
31 // Info logs to INFO log. Arguments are handled in the manner of fmt.Print.
32 Info(args ...any)
33 // Infoln logs to INFO log. Arguments are handled in the manner of fmt.Println.
34 Infoln(args ...any)
35 // Infof logs to INFO log. Arguments are handled in the manner of fmt.Printf.
36 Infof(format string, args ...any)
37 // Warning logs to WARNING log. Arguments are handled in the manner of fmt.Print.
38 Warning(args ...any)
39 // Warningln logs to WARNING log. Arguments are handled in the manner of fmt.Println.
40 Warningln(args ...any)
41 // Warningf logs to WARNING log. Arguments are handled in the manner of fmt.Printf.
42 Warningf(format string, args ...any)
43 // Error logs to ERROR log. Arguments are handled in the manner of fmt.Print.
44 Error(args ...any)
45 // Errorln logs to ERROR log. Arguments are handled in the manner of fmt.Println.
46 Errorln(args ...any)
47 // Errorf logs to ERROR log. Arguments are handled in the manner of fmt.Printf.
48 Errorf(format string, args ...any)
49 // Fatal logs to ERROR log. Arguments are handled in the manner of fmt.Print.
50 // gRPC ensures that all Fatal logs will exit with os.Exit(1).
51 // Implementations may also call os.Exit() with a non-zero exit code.
52 Fatal(args ...any)
53 // Fatalln logs to ERROR log. Arguments are handled in the manner of fmt.Println.
54 // gRPC ensures that all Fatal logs will exit with os.Exit(1).
55 // Implementations may also call os.Exit() with a non-zero exit code.
56 Fatalln(args ...any)
57 // Fatalf logs to ERROR log. Arguments are handled in the manner of fmt.Printf.
58 // gRPC ensures that all Fatal logs will exit with os.Exit(1).
59 // Implementations may also call os.Exit() with a non-zero exit code.
60 Fatalf(format string, args ...any)
61 // V reports whether verbosity level l is at least the requested verbose level.
62 V(l int) bool
63}
64
65// DepthLoggerV2 logs at a specified call frame. If a LoggerV2 also implements
66// DepthLoggerV2, the below functions will be called with the appropriate stack
67// depth set for trivial functions the logger may ignore.
68//
69// # Experimental
70//
71// Notice: This type is EXPERIMENTAL and may be changed or removed in a
72// later release.
73type DepthLoggerV2 interface {
74 LoggerV2
75 // InfoDepth logs to INFO log at the specified depth. Arguments are handled in the manner of fmt.Println.
76 InfoDepth(depth int, args ...any)
77 // WarningDepth logs to WARNING log at the specified depth. Arguments are handled in the manner of fmt.Println.
78 WarningDepth(depth int, args ...any)
79 // ErrorDepth logs to ERROR log at the specified depth. Arguments are handled in the manner of fmt.Println.
80 ErrorDepth(depth int, args ...any)
81 // FatalDepth logs to FATAL log at the specified depth. Arguments are handled in the manner of fmt.Println.
82 FatalDepth(depth int, args ...any)
83}
84
85const (
86 // infoLog indicates Info severity.
87 infoLog int = iota
88 // warningLog indicates Warning severity.
89 warningLog
90 // errorLog indicates Error severity.
91 errorLog
92 // fatalLog indicates Fatal severity.
93 fatalLog
94)
95
96// severityName contains the string representation of each severity.
97var severityName = []string{
98 infoLog: "INFO",
99 warningLog: "WARNING",
100 errorLog: "ERROR",
101 fatalLog: "FATAL",
102}
103
104// sprintf is fmt.Sprintf.
105// These vars exist to make it possible to test that expensive format calls aren't made unnecessarily.
106var sprintf = fmt.Sprintf
107
108// sprint is fmt.Sprint.
109// These vars exist to make it possible to test that expensive format calls aren't made unnecessarily.
110var sprint = fmt.Sprint
111
112// sprintln is fmt.Sprintln.
113// These vars exist to make it possible to test that expensive format calls aren't made unnecessarily.
114var sprintln = fmt.Sprintln
115
116// exit is os.Exit.
117// This var exists to make it possible to test functions calling os.Exit.
118var exit = os.Exit
119
120// loggerT is the default logger used by grpclog.
121type loggerT struct {
122 m []*log.Logger
123 v int
124 jsonFormat bool
125}
126
127func (g *loggerT) output(severity int, s string) {
128 sevStr := severityName[severity]
129 if !g.jsonFormat {
130 g.m[severity].Output(2, sevStr+": "+s)
131 return
132 }
133 // TODO: we can also include the logging component, but that needs more
134 // (API) changes.
135 b, _ := json.Marshal(map[string]string{
136 "severity": sevStr,
137 "message": s,
138 })
139 g.m[severity].Output(2, string(b))
140}
141
142func (g *loggerT) printf(severity int, format string, args ...any) {
143 // Note the discard check is duplicated in each print func, rather than in
144 // output, to avoid the expensive Sprint calls.
145 // De-duplicating this by moving to output would be a significant performance regression!
146 if lg := g.m[severity]; lg.Writer() == io.Discard {
147 return
148 }
149 g.output(severity, sprintf(format, args...))
150}
151
152func (g *loggerT) print(severity int, v ...any) {
153 if lg := g.m[severity]; lg.Writer() == io.Discard {
154 return
155 }
156 g.output(severity, sprint(v...))
157}
158
159func (g *loggerT) println(severity int, v ...any) {
160 if lg := g.m[severity]; lg.Writer() == io.Discard {
161 return
162 }
163 g.output(severity, sprintln(v...))
164}
165
166func (g *loggerT) Info(args ...any) {
167 g.print(infoLog, args...)
168}
169
170func (g *loggerT) Infoln(args ...any) {
171 g.println(infoLog, args...)
172}
173
174func (g *loggerT) Infof(format string, args ...any) {
175 g.printf(infoLog, format, args...)
176}
177
178func (g *loggerT) Warning(args ...any) {
179 g.print(warningLog, args...)
180}
181
182func (g *loggerT) Warningln(args ...any) {
183 g.println(warningLog, args...)
184}
185
186func (g *loggerT) Warningf(format string, args ...any) {
187 g.printf(warningLog, format, args...)
188}
189
190func (g *loggerT) Error(args ...any) {
191 g.print(errorLog, args...)
192}
193
194func (g *loggerT) Errorln(args ...any) {
195 g.println(errorLog, args...)
196}
197
198func (g *loggerT) Errorf(format string, args ...any) {
199 g.printf(errorLog, format, args...)
200}
201
202func (g *loggerT) Fatal(args ...any) {
203 g.print(fatalLog, args...)
204 exit(1)
205}
206
207func (g *loggerT) Fatalln(args ...any) {
208 g.println(fatalLog, args...)
209 exit(1)
210}
211
212func (g *loggerT) Fatalf(format string, args ...any) {
213 g.printf(fatalLog, format, args...)
214 exit(1)
215}
216
217func (g *loggerT) V(l int) bool {
218 return l <= g.v
219}
220
221// LoggerV2Config configures the LoggerV2 implementation.
222type LoggerV2Config struct {
223 // Verbosity sets the verbosity level of the logger.
224 Verbosity int
225 // FormatJSON controls whether the logger should output logs in JSON format.
226 FormatJSON bool
227}
228
229// combineLoggers returns a combined logger for both higher & lower severity logs,
230// or only one if the other is io.Discard.
231//
232// This uses io.Discard instead of io.MultiWriter when all loggers
233// are set to io.Discard. Both this package and the standard log package have
234// significant optimizations for io.Discard, which io.MultiWriter lacks (as of
235// this writing).
236func combineLoggers(lower, higher io.Writer) io.Writer {
237 if lower == io.Discard {
238 return higher
239 }
240 if higher == io.Discard {
241 return lower
242 }
243 return io.MultiWriter(lower, higher)
244}
245
246// NewLoggerV2 creates a new LoggerV2 instance with the provided configuration.
247// The infoW, warningW, and errorW writers are used to write log messages of
248// different severity levels.
249func NewLoggerV2(infoW, warningW, errorW io.Writer, c LoggerV2Config) LoggerV2 {
250 flag := log.LstdFlags
251 if c.FormatJSON {
252 flag = 0
253 }
254
255 warningW = combineLoggers(infoW, warningW)
256 errorW = combineLoggers(errorW, warningW)
257
258 fatalW := errorW
259
260 m := []*log.Logger{
261 log.New(infoW, "", flag),
262 log.New(warningW, "", flag),
263 log.New(errorW, "", flag),
264 log.New(fatalW, "", flag),
265 }
266 return &loggerT{m: m, v: c.Verbosity, jsonFormat: c.FormatJSON}
267}